1. Field of the Invention
The present invention relates to a paper feed cassette of an image forming device such as a facsimile machine and a copier. More specifically, the present invention relates to a technique for a side guide that guides a recording paper placed on the paper feed cassette to a prescribed position.
2. Description of the Related Art
A conventional image forming device such as a facsimile machine or a copier is provided with a paper feed unit. A paper feed cassette, which constitutes a portion of the paper feed unit, includes a flapper on which recording papers are placed, a pick up roller for picking up the recording papers on the flapper one sheet at a time and supplying the recording papers to an image recording unit, and a pair of side guides for guiding the recording papers on the flapper to a prescribed position and aligning a position of an end portion of the recording papers by making contact with the end portion of the recording papers. The side guides are arranged opposite to each other such that the side guides guide both side portions of the recording papers with respect to a transporting direction of the recording papers. The recording papers are positioned by placing the side guides along the respective end portions of the recording papers. The side guides are provided with a guide width adjusting mechanism so that the side guides can slide from side to side in accordance with a size of the recording papers.
The side guides are formed of synthetic resin or a metal plate. Thus formed side guides are required to achieve predetermined intensity so that the recording papers accommodated in the paper feed cassette will not be deformed by a load of the recording papers or the recording papers will not be displaced by an impact generated when opening and closing the paper feed cassette. Further, the side guides are provided with the guide width adjusting mechanism that adjusts a guide width. Consequently, the side guides have a complex structure.
By integrally forming the side guides with synthetic resin entirely, although the side guides have the complex structure, a configuration thereof can be relatively simple, and a number of components can be reduced. However, in order for the resin side guides to achieve a predetermined intensity, a thickness of a member of the side guides is required to be relatively thick. However, a problem is that in order to place the side guides with the thick member in the paper feed cassette, a large space is required in the paper feed cassette.
By forming the side guides with a metal plate entirely, even if the thickness of the member of the side guides is decreased, the predetermined intensity can be achieved. Therefore, a space for accommodating the side guides in the paper feed cassette can be reduced. However, only a simple shape can be formed by press working a metal plate etc., which makes it difficult to form the side guides with the complex structure. Therefore, a problem is that due to an increase of the number of components and an assembly process of the components, a manufacturing cost increases.